The invention relates to novel hydrogenated fructooligosaccharides of the type (fructosyl).sub.n mannitol and (fructosyl).sub.n sorbitol which are suitable as sweeteners, and to processes for their preparation.
An increasing awareness of nutrition has placed special demands on food, and in particular on sweeteners. These include:
1. Non-cariogenicity; the sweetener should not be harmful to teeth. It should not be able to be converted by microorganisms present in the mouth either to acids or to plaque-forming polysaccharides. PA1 2. Suitability for diabetics; the sweetener should not cause elevated insulin secretion on consumption. It is desirable that the sweetener delays the resorption of other dietary constituents by inhibition of the enzyme activity in the small intestine and thus leads to avoidance of insulin peaks. PA1 3. Decreased caloric yield; the sweetener should not be able to be metabolized by the human organism. It is additionally advantageous if the sweetener, by inhibiting the enzyme activity in the small intestine, delays the absorption of other dietary constituents and as a result leads to a lower caloric uptake overall. PA1 4. The sweetener should promote the multiplication of bifidogenic microorganisms in the large intestine region. PA1 5. The sweetener should have a purely sweet taste and be able to be processed in foods under the most varied conditions (e.g., broad temperature or pH ranges).
Sucrose, known to humans since antiquity, only complies with the last mentioned requirement. Attempts are therefore being made to find alternative sweeteners which also comply with the other requirements.
It is known to use xylitol as a noncariogenic sweetener suitable for diabetics (A. B ar in Alternative Sweeteners, L. O'B. Nabors and R. C. Gelardi (ed.), Marcel Dekker, New York, 1986). However, at 4 kcal/g, it has the same nutritional value as sucrose. As a result of the high endothermic heat of solution, the use of xylitol in a number of foods is problematic. Moreover, xylitol can only be used with great limitations in bakery products and hard toffees. A further disadvantage of xylitol is that the price is relatively high for a sweetener.
A further sweetener which is not harmful to teeth and is suitable for diabetics is sorbitol (B. K. Dwivedi in Alternative Sweeteners, L. O'B. Nabors and R. C. Gelardi (ed.), Marcel Dekker, New York, 1986). The disadvantages listed under xylitol also apply equally to sorbitol (with the exception of the price which is not so high).
Hydrogenated starch hydrolysates are also known as alternative sweeteners (B. K. Dwivedi in Alternative Sweeteners, L. O'B. Nabors and R. C. Gelardi (ed.), Marcel Dekker, New York, 1986). These can be hydrolyzed in the small intestine and, because they release glucose in the course of this, they are unsuitable for diabetics. Their potential use in foods is otherwise also relatively restricted because of unfavorable physical properties.
Crystalline fructose is another sweetener having interesting physiological properties (T. F. Osberger in Alternative Sweeteners, L. O'B. Nabors and R. C. Gelardi (ed.), Marcel Dekker, New York, 1986) but it also exhibits serious disadvantages. The sweetening power of fructose is dependent on the temperature, as a result of which correct dosing in foods is problematic. As a result of the low thermal stability of fructose, its use in foods which are cooked or baked is possible only with great restrictions.
Isomalt, a tooth-friendly low-calorie sweetener which is suitable for diabetics (P. J. Str ater in Alternative Sweeteners, L. O'B. Nabors and R. C. Gelardi (ed.), Marcel Dekker, New York, 1986), in comparison to sucrose, has insufficient solubility in water, as a result of which it can crystallize out in foods having a high dry matter content (e.g. jams).
An object of the present invention therefore is to provide a sweetener which
1) has a sweet taste comparable to that of sucrose; PA0 2) can be easily processed in foods; PA0 3) does not cause or promote dental caries or plaque formation; PA0 4) does not cause elevated insulin values in the blood on consumption; PA0 5) is not itself, or is only in part, calorically utilizable; PA0 6) inhibits the enzyme complexes of the small intestine mucosa and as a result decreases the caloric utilization of other carbohydrates; PA0 7) promotes the multiplication of bifidogenic microorganisms in the large intestine region; and PA0 8) is readily and inexpensively accessible from natural sources.